Elaborating on and defending a rigorous, rights-based libertarianism, Mark D. Friedman here develops the seminal ideas articulated by Robert Nozick in his landmark work Anarchy, State and Utopia. Consolidating more than three decades of scholarly and popular writing to have emerged in the wake of Nozick's text, Friedman offers a 21st-century defense of the minimal libertarian state. In the course of this analysis, and drawing on further insights offered by the work of F.A. Hayek, Nozick's Libertarian Project shows that natural rights libertarianism can offer convincing answers to the fundamental questions that lie at the heart of political theory. The book also rebuts many of the most common criticisms to have been levelled at this worldview, including those from left libertarians and from egalitarians such as as G.A. Cohen.